In Ecuador, the Organic Law on Disabilities is in force, which, among other things, regulates priority care in accessible web portals. In addition, there is the NTE INEN-ISO/IEC 40500 standard that defines the characteristics that an accessible website should have. This study identified the absence of the application of the Ecuadorian standard by web developers in the central region of the country, since 57% are unaware of the existence of the standard and the others do not know how to apply it; consequently, in this research the Kanban methodology was used to develop a detailed manual of how the principles and guidelines established in the standard should be applied for the development of accessible web interfaces. Based on the guide, 4 prototypes of websites were developed to verify the usefulness of the manual. For the technical evaluation, the WAVE tool was used, which demonstrated that the sites meet the accessibility requirements, without access or contrast errors. The results of this research highlight the importance of having practical manuals to implement web accessibility standards. This research serves as a reference for web developers and designers, thus guaranteeing the digital inclusion of people with visual and auditory disabilities.